The prior art has disclosed methods for positively influencing the performance data of engines with internal combustion, for example a gas turboset, by evaporative cooling before and/or during the compression of the combustion air. For this purpose, it is customary for water or another liquid to be injected in finely atomized form into the gas stream which has been drawn in. The overriding significance of the atomization quality and the homogeneous distribution of the liquid introduced was recognized as early as in FR 1 563 749. The drop size directly influences the flow-following capacity and the evaporation time of the drops. When drops enter a turbo-compressor, the number of drops which strike the compressor blades, and the potentially erosive effect thereof, increases with the drop size. This means that if the drop size exceeds a defined limit value, the negative effects rise disproportionately. Therefore, U.S. Pat. No. 6,216,443 indicates injecting drops of a size of from 1 to 50 μm diameter into the compressor of a gas turboset. This size depends on a large number of different parameters, such as inter alia nozzle geometry, atomization pressure or the flow conditions following atomization. These parameters are subject to potential changes in long-term operation: erosive or blocking of atomizer nozzles are only some of the processes which can change the atomization characteristics of an injection apparatus in the long term.
US 2001/002078 and WO 2004/025102 have disclosed methods in which a mass flow of liquid is injected in atomized form into the air intake duct of an engine. The injection is operated in a closed control circuit by means of sensors arranged downstream of the injection, and the injected mass flow is adjusted until a desired value for the measured values is reached. The variables measured in this case, however, also do not provide any information as to the atomization characteristics.